This study will investigate the hemoglobin cooperativity mechanism and myoglobin ligand bonding to elucidate the protein constraints which control ligand affinity in heme proteins. The differences in heme-globin interactions which permit hemoglobin to serve as an efficient oxygen transport protein and myoglobin to serve as an oxygen storage protein in muscle will be examined. The new spectroscopic technique of UV resonance Raman spectroscopy will be developed for this study and used in conjunction with IR and x-ray diffraction to probe molecular questions such as the aromatic amino acid role in the protein structural changes which accompany the cooperative binding of oxygen. This study will develop techniques to correlate changes in resonance Raman intensities with changes in the globin structure and changes in the intermolecular interactions between aromatic amino acids and adjacent residues. Resonance Raman studies of the heme and its constellation of ligands will relate heme bonding and geometric changes to globin conformational changes. A novel combined X-ray and Raman study of uniaxially strained model compounds will, for the first time, directly correlate Raman frequencies to bond distances. Intermolecular interactions between the heme ligand and residues on the distal side of the globin will be studied by using IR and Raman spectroscopy. This study will develop a new molecular understanding of allosteric enzyme mechanisms, and will develop a new spectroscopic technique, UV resonance Raman spectroscopy, as a probe of biomolecular structure.